Plating and anodizing bath racks

ABSTRACT

A plating or anodizing rack with a supporting structure having at least one socket recess through it and a detachable spring clip inserted into the recess. The clip has a U-shaped resilient body with two arms extending from a junction point, the edges of the clip making a line contact with the surface of the recess and frictionally engage it.

United States Patent [72] Inventor Paul A. Chenevier Lugarno, New SouthWales, Australia [21] Appl. No. 758,833 [22] Filed Sept. 10, I968 [45]Patented Sept. 21, 1971 [73] Assignee Raynors Pty. Limited Punchbowl,New South Wales, Australia [32] Priority Feb. 5, 1968 [33] Australia [3133082/68 [54] PLATING AND ANODlZlNG BATH RACKS 4 Claims, ll DrawingFigs.

[52] U.S. Cl 204/297 R [5]] int. Cl C23b 5/70 [50] Field oi Search204/297 [56] References Cited UNITED STATES PATENTS 3,429,786 2/l969Kubik 204/297 2,793,994 5/1957 Novitsky 204/297 Primary Examiner-John H.Mack Assistant Examiner-Sidney S. Kanter Attorney-Stevens, Davis, Miller& Mosher ABSTRACT: A plating or anodizing rack with a supportingstructure having at least one socket recess through it and a detachablespring clip inserted into the recess. The clip has a U-shaped resilientbody with two arms extending from a junction point, the edges of theclip making a line contact with the surface of the recess andfrictionally engage it.

PATENTEU strzl I971 SHEET 1 OF 2 PATENTEU SEPZI l9?! 3,607,707

sum 2 or 2 PLATING AND ANODIZING BATH RACKS This invention relates tothe racks used to support articles for treatment of electroplating oranodizing baths.

Such racks usually comprise a spine or frame adapted to be hung from anoverhead bus bar furnished with a plurality of spring clips adapted togrip the articles to be treated.

Hitherto the spring clips have been riveted, bolted, welded or otherwisemore or less permanently secured to the spine or frame.

The effective life of prior used racks is short for not only are thebath liquids usually highly corrosive, but also anodizing racks tend tobe dissolved or eroded by the chemical and/or electrolytic actioninvolved and plating racks are subject to metal buildup on all exposedmetal surfaces.

Both these effects are wasteful of material and otherwise objectionableand eventually render normal racks unfit for use; in the case ofanodizing racks because the mechanical strength or current carryingcapacity of the rack is reduced to an unsatisfactory value and in thecase of plating racks because the metal buildup on the tips of thespring clips (which are necessarily exposed to make electrical contactwith the workpieces) destroys their ability to grip the articlessatisfactorily. Furthermore pieces of the built up metal break free fromthe clips and contaminate the bath.

in view of the foregoing it has hitherto been necessary to discardanodizing racks after a short period of use and to dismantle and serviceplating racks at frequent intervals.

it is possible to make anodizing racks from titanium which does notcorrode in the bath but the high cost of this expedient has preventedits wide spread adoption.

The problem of metal buildup on the tips of the clips of prior knownplating racks has been overcome either by timeconsuming manual removalof the built-up metal or by immersing the rack in a corrosive cleaningacid to dissolve the built-up metal. The clips of prior known platingracks have usually been made of stainless steel or other metal resistantto the action of such a cleaning acid but it frequently happens that theprotective insulating coating on the rack itself becomes damaged, inwhich event, it also is attacked by the cleaning acid.

Conceivably, this could be overcome by making the entire rack ofstainless steel but, once again, the high cost of material is anobstacle. Furthermore, as the insulating coating of a proportion ofracks remains intact through their useful life it would be wasteful tomake all racks from stainless steel.

The costs of using titanium and stainless steel as aforesaid areexcessive because as a general rule hitherto each rack has been tailoredto the articles to be treated so that different racks have been requirefor each change in product. lndeed any large anodizing or plating plantusually has a large amount of capital tied up in stocks of used racksnot immediately needed by retained in store to meet possible repeatorders and the like.

Therefore it would be desirable to make use of adjustable or universalracks each able to handle a wide range of products if only as it wouldthen be economic to use the above-mentioned materials. Also such rackswould enable a desirable reduction in the stock of racks to be achievedirrespective of the material used.

Hitherto it has been proposed to make racks of an adjustable nature byusing demountable frames, that is to say frames made from reusablecomponents which may be bolted or' otherwise nonpermanently securedtogether in a variety of ways; but this expedient is only of limited useas it does not provide for variation of the spring clips associated witheach frame component.

In view of the foregoing the present invention was devised to provideracks, preferably of the demountable type, wherein the spring clips arereadily removable and replaceable.

According to the invention a plating or anodizing rack is providedcomprising a supporting structure, for example a spine or frame, havingat least one socket recess formed in it and at least one, detachablespring clip comprising a U-shaped resilient body, in the form of twoarms extending from a junction portion, adapted to be inserted into saidrecess and to be retained therein by friction, and gripping means onsaid body adopted to engage an article to be supported by the rack; thearrangement being such that, when the clip body is inserted into saidrecess, the gripping means are disposed outside the recess.

The invention extends not only to a rack as aforesaid but also the tothe above-described clips for the rack.

According to preferred embodiments of the abovedescribed invention, thesupporting structure comprises a spine or demountable frame whereof theclip carrier component, or each of them, is a rectangular sectionedmetal bar with a plurality of spaced-apart holes drilled through itdisposed in a row extending longitudinally of the bar; said holesconstituting the socket recesses for the clips. Alternatively, shortlengths of tubing or the like may be welded or otherwise secured to thebar so as to project therefrom, in which event the bore of each piece oftubing constitutes a socket recess. A

For preference the body portion of each clip is formed from a length ofresilient metal strap of rectangular cross section bent into a U shape.

The body portion of the strip is preferably formed so that the armsnaturally slightly diverge, but are brought towards each other byresilient deformation of the clip junction portion when the body portionis thrust into a socket recess.

Accordingly when a socket recess is a circular cross section (as ispreferred) each of the outer edges of the clip arms makes high-pressureline contact with the side surfaces of the recess. This serves to holdthe clips in place securely and to produce a good electrical connectionbetween the clip and supporting bar in which the socket recess isformed.

The arms of the clip protruding from the recess may themselves grip thearticle to be treated. For example, each arm may diverge from the otherrapidly outside of the recess, except for the free end portions of thearms which may be returned so that the arm tips are directed towardseach other. Those tips may be formed with one or more points so thatthey make high-pressure point contact with an article lodged betweenthem.

According to other embodiments of the invention only one of the cliparms may extend substantially from the socket recess in which case saidone arm coacts with the corresponding arm of another clip in anothersocket recess to grip an article between them.

According to still other embodiments of the invention the U-shaped bodyportion, or rather one arm thereof, which projects from the socketrecess carries more or less elaborate gripping means of any conventionalkind adapted to hold an article to be treated.

Plating racks according to the invention preferably have all surfaces ofthe supporting structure, except those defining the socket recess,covered with a plastics insulating layer to prevent plating metalbuildup thereon.

The side surfaces of the said recesses are left bare so that electricalconnection maybe effected with the clips, and it has been found inexperiments leading to the present invention that those surfaces arepartly shielded from plating currents by the clip so that metal buildupis only slow. Such metal as does buildup on the socket surface may beremoved periodically by a simple reaming operation by unskilled labor.

It will be noted that the preferred embodiments of the invention, asdescribed above, are such that the placement of an article to be treatedinto position imposes loads on the body portion of the clips holding itwhich tend to separate the clip body arms. Thus clips may be made sothat they are very readily removed and replaced when unloaded, but whichbecome tightly held in position when in use holding an article.

By way of example, several embodiments of the abovedescribed inventionare described hereinafter with reference to the accompanying drawings.

FIG. 1 is a front elevational of an anodizing rack according to theinvention.

FIG. 2 is a side elevation of the rack of FIG. 1.

FIG. 3 is a sectional view taken on line 3-3 of FIG. 1 but drawn to alarger scale.

FIG. 4 is a plan view taken on line 4-4 of FIG. 3.

FIG. 5 is a front elevation of a plating rack according to theinvention.

FIG. 6 is a side elevation of the rack of FIG. 5.

FIG. 7 is a sectional view taken on line 77 of FIG. 5.

FIGS. 8, 9, 10 and 1 l are perspective views of various spring clipsaccording to the invention usable as components of plating anodizingracks according to the invention.

The plating rack illustrated in FIGS. 1 to 4 comprises a demountableframe 12 comprising longitudinally slotted side members 13 of titaniumand upper and lower crossmembers 14 and 15 respectively.

The upper end of each side member 13 is provided with a suspension hook16 whereby the rack as a whole may be suspended from a bus bar 17extending above an anodizing bath with the main part of the rackimmersed in the electrolyte.

The suspension hooks 16 are secured to the side members 13 bythrough-bolts l8 and clamping plates 19.

Similarly the lower crossmember 15 is secured to the side members 13 bymeans of through-bolts 20 extending through upwardly directed affixturelugs 21 on the crossmember 15 and clamping plates 22.

The upper crossmember I4 is likewise secured to the side members 13 bymeans of downwardly directed affixture lugs 23, clamping plates 24 andthrough-bolts 25. It will be clear that the upper member 14 may,therefore, be positioned at any desired spacing from the lower member 15within the limits imposed by the lengths of the side members 13.

The upper crossmember I4 is pierced by a row of holes 26 each of whichconstitute a socket recess for the reception of a spring clip 27.

Each of the clips 27 is made from a length of resilient metal strap ofrectangular cross section and comprises a U-shaped body comprising twoarms 28 extending from a junction portion 29 able to be inserted into acorresponding one of the recesses 26 to be retained therein by frictionbetween the arms 29 and the inner surface and/or rim of the socketrecess. In the embodiment of the invention now being discussed the arms28 are prolonged and terminate in inwardly directed tips 30 adapted togrip the upper end of an article 31 to be anodizing.

The plate rack illustrated by FIGS. 5 and 7 comprises a metal spine 31provided with a suspension hook 32 at its top end and with a pluralityof short tubular sockets 33 welded or otherwise secured to it. The spine31 and the outer surfaces of the sockets 33 are coated with a corrosionresistant, plastics, insulating coating of known kind. The bore of eachof the sockets 33 constitutes a socket recess adapted to receive andretain spring clips 34.

Each of the clips 34 may be the same or similar to the clip illustratedby FIG. 8. and, in that event, comprise a resilient metal strap formedinto a U-shaped body comprising two arms 35 and a junction portion 36.In this instance also the arms 35 are extended and terminate in inwardlydirected tips 37 adapted to hold an article to be placed between them.The clip body and the tips of its arms are bare but the prolongations ofthe arms 35 are coated with corrosion resistant plastics material at 38.

The clip illustrated by FIG. 9 comprises a resilient U-shaped body 39 ofwhich one arm 40 projects for the support of a crossbar 41 havingoutwardly directed tips 42. The arm 40 and the crossbar 41 (except forits tips 42) are coated with plastics material.

The clip of FIG. 9 is intended to coact with a neighboring clip of thesame general construction for the support of an article to be plated andin this regard differs from the clip of FIG. 8 which is adapted to graspan article without assistance from another clip.

The spring clip of FIG. 10 is similar to that of FIG. 9 except in thatthe crossbar 41 is replaced by two resilient wire crossbars 43 the endsof which are uncoated for contact with the arexcept for a variation inthe shape of its U-shaped body 44 to suit a somewhat larger socketorifice than that to which the clip of FIG. 9 is suited.

It must be emphasized that the above-illustrated clips are only examplesof a virtually limitless variety of clips adapted to the support of allmanner of articles required to be anodized or electroplated. In everyinstance, however, a clip according to the invention may bedistinguished because of its U-shaped body portion whereby it is securedin its associated socket orifice. Furthermore, it will be appreciatedthat the rack frame is also subject to great variety in design dependingupon the article to be treated and, therefore, the examples of theinvention illustrated and described above are not to be taken aslimiting, the scope of the invention being as defined in theaccompanying claims.

I claim:

1. A plating or anodizing rack comprising a support structure having atleast one socket recess extending through it and at least one detachablespring clip comprising a U-shaped resilient body, in the form of twoarms extending from a junction portion, inserted into said recess andretained therein by friction, gripping means extending from said bodyadapted to engage an article to be supported by the rack; thearrangement being such that the gripping means are disposed outside saidrecess and the edges of the body make line contacts with the surface ofsaid recess.

2. A rack, according to claim I, wherein said gripping means comprise anintegral extension of at least one of said arms.

3. A rack, according to claim 1, wherein said supporting structurecomprises a plurality of frame members bolted or otherwisedetachablysecured together.

4. A rack, according to claim 1, wherein said gripping means are suchthat engagement with the article thereby tends to spread the clip armsapart.

2. A rack, according to claim 1, wherein said gripping means comprise anintegral extension of at least one of said arms.
 3. A rack, according toclaim 1, wherein said supporting structure comprises a plurality offrame members bolted or otherwise detachably secured together.
 4. Arack, according to claim 1, wherein said gripping means are such thatengagement with the article thereby tends to spread the clip arms apart.